1. Field of the Invention
The present invention relates to an image display apparatus, and, more particularly to a technology for an image display apparatus that displays an image by transmitting light corresponding to an image signal through a screen.
2. Description of the Related Art
In an image display apparatus that displays an image by transmitting light corresponding to an image signal, for example, a rear projector, a reduction in thickness of a housing is realized by making the light obliquely incident on a screen (see, for example, Japanese Patent Application Laid-Open No. S61-275831, Japanese Patent Application Laid-Open No. 2005-84576, and Japanese Patent Application Laid-Open No. 2002-207190).
In the image display apparatus, for improvement of designability and the like, it is desired to make a non-display section adjacent to the screen as small as possible. There is also an advantage that it is possible to display a large image with a small housing by forming the non-display section adjacent to the screen as small as possible. For example, in the structure shown in FIG. 8 of Japanese Patent Application Laid-Open No. S61-275831, since an optical engine unit and a project lens are housed in a space below the screen in the housing, a large non-display section is formed. In the structure proposed in Japanese Patent Application Laid-Open No. 2005-84576 and the structure proposed in Japanese Patent Application Laid-Open No. 2002-207190, a non-display section below a screen is reduced by arranging an optical engine unit and the like on the rear side of the screen. Concerning both the technologies of Japanese Patent Application Laid-Open No. 2005-84576 and Japanese Patent Application Laid-Open No. 2002-207190, it is considered that it depends on arrangement of respective units of an optical system, in particular, an aspherical mirror and a projection optical system whether it is possible to accurately cause light to travel in the entire structures disclosed. However, there is no specific definition about the arrangement of the respective units of the optical system in the documents described above. Therefore, according to the conventional technologies, there is a problem in that it is impossible to accurately cause light to travel to pass through a desired optical path depending on the arrangement of the respective units and the optical system itself is not effective.
The present invention has been devised in view of the problem and an advantage of some aspects of the present invention is to provide an image display apparatus in which a non-display section adjacent to a screen is small and that is capable of accurately causing light to travel to display an image in a thin structure.